Java example source code file (MetalworksHelp.java)

This example Java source code file (MetalworksHelp.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

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Java - Java tags/keywords

cursor, document, event, gui, htmlpane, ioexception, jeditorpane, jinternalframe, jscrollpane, jviewport, leakingthisinconstructor, malformedurlexception, metalworkshelp, net, network, pageloader, suppresswarnings, swing, text, url

The MetalworksHelp.java Java example source code

/*
 * Copyright (c) 1998, 2011, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * This source code is provided to illustrate the usage of a given feature
 * or technique and has been deliberately simplified. Additional steps
 * required for a production-quality application, such as security checks,
 * input validation and proper error handling, might not be present in
 * this sample code.
 */



import javax.swing.*;
import java.awt.*;
import java.net.URL;
import java.net.MalformedURLException;
import java.io.*;
import javax.swing.text.*;
import javax.swing.event.*;


/**
 * @author Steve Wilson
 * @author Alexander Kouznetsov
 */
@SuppressWarnings("serial")
public class MetalworksHelp extends JInternalFrame {

    public MetalworksHelp() {
        super("Help", true, true, true, true);

        setFrameIcon((Icon) UIManager.get("Tree.openIcon")); // PENDING(steve) need more general place to get this icon
        setBounds(200, 25, 400, 400);
        HtmlPane html = new HtmlPane();
        setContentPane(html);
    }
}


@SuppressWarnings("serial")
class HtmlPane extends JScrollPane implements HyperlinkListener {

    JEditorPane html;

    @SuppressWarnings("LeakingThisInConstructor")
    public HtmlPane() {
        try {
            URL url = getClass().getResource("/resources/HelpFiles/toc.html");
            html = new JEditorPane(url);
            html.setEditable(false);
            html.addHyperlinkListener(this);
            html.putClientProperty(JEditorPane.HONOR_DISPLAY_PROPERTIES,
                    Boolean.TRUE);
            JViewport vp = getViewport();
            vp.add(html);
        } catch (MalformedURLException e) {
            System.out.println("Malformed URL: " + e);
        } catch (IOException e) {
            System.out.println("IOException: " + e);
        }
    }

    /**
     * Notification of a change relative to a
     * hyperlink.
     */
    public void hyperlinkUpdate(HyperlinkEvent e) {
        if (e.getEventType() == HyperlinkEvent.EventType.ACTIVATED) {
            linkActivated(e.getURL());
        }
    }

    /**
     * Follows the reference in an
     * link.  The given url is the requested reference.
     * By default this calls <a href="#setPage">setPage,
     * and if an exception is thrown the original previous
     * document is restored and a beep sounded.  If an
     * attempt was made to follow a link, but it represented
     * a malformed url, this method will be called with a
     * null argument.
     *
     * @param u the URL to follow
     */
    protected void linkActivated(URL u) {
        Cursor c = html.getCursor();
        Cursor waitCursor = Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR);
        html.setCursor(waitCursor);
        SwingUtilities.invokeLater(new PageLoader(u, c));
    }


    /**
     * temporary class that loads synchronously (although
     * later than the request so that a cursor change
     * can be done).
     */
    class PageLoader implements Runnable {

        PageLoader(URL u, Cursor c) {
            url = u;
            cursor = c;
        }

        public void run() {
            if (url == null) {
                // restore the original cursor
                html.setCursor(cursor);

                // PENDING(prinz) remove this hack when
                // automatic validation is activated.
                Container parent = html.getParent();
                parent.repaint();
            } else {
                Document doc = html.getDocument();
                try {
                    html.setPage(url);
                } catch (IOException ioe) {
                    html.setDocument(doc);
                    getToolkit().beep();
                } finally {
                    // schedule the cursor to revert after
                    // the paint has happended.
                    url = null;
                    SwingUtilities.invokeLater(this);
                }
            }
        }
        URL url;
        Cursor cursor;
    }
}